Sudden loss of balance. The treatment?

Yesterday I had a sudden loss of balance while in office and I was about to fall but somehow managed to avoid embarrassment. This lasted for a few seconds and recurred again 3-4 times but to a lesser extent. Last month I had a severe pain from the back of the neck through to shoulder, hand and upto my fingers on the left side. Consulted a doc, who prescribed Nuroday PSR (10 days, 1 tab) and Neorelex MR 8 (5 days, 2 tabs), post which the pain was gone. More than a year ago I had mild hand tremors (continuos) and showed a doctor who said it was too mild for treatment and to come back if it increased. I then did hand exercise which helped to reduce. However last 3 months these have more or less disappeared and currently I don't have them. In addition I am a thyroid patient, regularly take Thyronorm 88mcg / 100mcg alternate days What is the reason for the sudden imbalance and what is the treatment?